feat(gantt): introduce advanced Gantt chart components and demo page

- Added new components for an advanced Gantt chart, including AdvancedGanttChart, GanttGrid, DraggableTaskBar, and TimelineMarkers.
- Implemented a demo page (GanttDemoPage) to showcase the functionality of the new Gantt chart components.
- Enhanced project roadmap features with ProjectRoadmapGantt and related components for better project management visualization.
- Introduced sample data for testing and demonstration purposes, improving the user experience in the Gantt chart interface.
- Updated main routes to include the new Gantt demo page for easy access.

worklenz-frontend/src/components/project-roadmap-gantt/PhaseModal.tsx

@@ -0,0 +1,406 @@
+import React, { useState } from 'react';
+import { 
+  Modal, 
+  Tabs, 
+  Progress, 
+  Tag, 
+  List, 
+  Avatar, 
+  Badge, 
+  Space, 
+  Button,
+  Statistic,
+  Row,
+  Col,
+  Timeline,
+  Input,
+  Form,
+  DatePicker,
+  Select
+} from 'antd';
+import { 
+  CalendarOutlined, 
+  TeamOutlined, 
+  CheckCircleOutlined, 
+  ClockCircleOutlined,
+  FlagOutlined,
+  ExclamationCircleOutlined,
+  EditOutlined,
+  SaveOutlined,
+  CloseOutlined
+} from '@ant-design/icons';
+import { PhaseModalData, ProjectPhase, PhaseTask, PhaseMilestone } from '../../types/project-roadmap.types';
+import { useAppSelector } from '../../hooks/useAppSelector';
+import { themeWiseColor } from '../../utils/themeWiseColor';
+import dayjs from 'dayjs';
+
+const { TabPane } = Tabs;
+const { TextArea } = Input;
+
+interface PhaseModalProps {
+  visible: boolean;
+  phase: PhaseModalData | null;
+  onClose: () => void;
+  onUpdate?: (updates: Partial<ProjectPhase>) => void;
+}
+
+const PhaseModal: React.FC<PhaseModalProps> = ({
+  visible,
+  phase,
+  onClose,
+  onUpdate,
+}) => {
+  const [isEditing, setIsEditing] = useState(false);
+  const [form] = Form.useForm();
+  
+  // Theme support
+  const themeMode = useAppSelector(state => state.themeReducer.mode);
+  const isDarkMode = themeMode === 'dark';
+
+  if (!phase) return null;
+
+  const handleEdit = () => {
+    setIsEditing(true);
+    form.setFieldsValue({
+      name: phase.name,
+      description: phase.description,
+      startDate: dayjs(phase.startDate),
+      endDate: dayjs(phase.endDate),
+      status: phase.status,
+    });
+  };
+
+  const handleSave = async () => {
+    try {
+      const values = await form.validateFields();
+      const updates: Partial<ProjectPhase> = {
+        name: values.name,
+        description: values.description,
+        startDate: values.startDate.toDate(),
+        endDate: values.endDate.toDate(),
+        status: values.status,
+      };
+      
+      onUpdate?.(updates);
+      setIsEditing(false);
+    } catch (error) {
+      console.error('Validation failed:', error);
+    }
+  };
+
+  const handleCancel = () => {
+    setIsEditing(false);
+    form.resetFields();
+  };
+
+  const getStatusColor = (status: string) => {
+    switch (status) {
+      case 'completed': return 'success';
+      case 'in-progress': return 'processing';
+      case 'on-hold': return 'warning';
+      default: return 'default';
+    }
+  };
+
+  const getPriorityColor = (priority: string) => {
+    switch (priority) {
+      case 'high': return 'red';
+      case 'medium': return 'orange';
+      case 'low': return 'green';
+      default: return 'default';
+    }
+  };
+
+  const getTaskStatusIcon = (status: string) => {
+    switch (status) {
+      case 'done': return <CheckCircleOutlined style={{ color: '#52c41a' }} />;
+      case 'in-progress': return <ClockCircleOutlined style={{ color: '#1890ff' }} />;
+      default: return <ExclamationCircleOutlined style={{ color: '#d9d9d9' }} />;
+    }
+  };
+
+  return (
+    <Modal
+      title={
+        <div className="flex justify-between items-center">
+          <Space>
+            <Badge status={getStatusColor(phase.status)} />
+            {isEditing ? (
+              <Form.Item name="name" className="mb-0">
+                <Input className="dark:bg-gray-700 dark:border-gray-600 dark:text-gray-100" />
+              </Form.Item>
+            ) : (
+              <h4 className="text-lg font-semibold text-gray-900 dark:text-gray-100 mb-0">
+                {phase.name}
+              </h4>
+            )}
+          </Space>
+          <Space>
+            {isEditing ? (
+              <>
+                <Button 
+                  type="primary" 
+                  icon={<SaveOutlined />} 
+                  onClick={handleSave}
+                  size="small"
+                >
+                  Save
+                </Button>
+                <Button 
+                  icon={<CloseOutlined />} 
+                  onClick={handleCancel}
+                  size="small"
+                  className="dark:border-gray-600 dark:text-gray-300"
+                >
+                  Cancel
+                </Button>
+              </>
+            ) : (
+              <Button 
+                type="text" 
+                icon={<EditOutlined />} 
+                onClick={handleEdit}
+                size="small"
+                className="dark:text-gray-300 dark:hover:bg-gray-700"
+              >
+                Edit
+              </Button>
+            )}
+          </Space>
+        </div>
+      }
+      open={visible}
+      onCancel={onClose}
+      width={800}
+      footer={null}
+      className="dark:bg-gray-800"
+    >
+      <Form form={form} layout="vertical">
+        <div className="mb-4">
+          {isEditing ? (
+            <Form.Item name="description" label={<span className="text-gray-700 dark:text-gray-300">Description</span>}>
+              <TextArea 
+                rows={2} 
+                className="dark:bg-gray-700 dark:border-gray-600 dark:text-gray-100" 
+              />
+            </Form.Item>
+          ) : (
+            <p className="text-gray-600 dark:text-gray-400">{phase.description}</p>
+          )}
+        </div>
+
+        {/* Phase Statistics */}
+        <Row gutter={16} className="mb-6">
+          <Col span={6}>
+            <div className="bg-gray-50 dark:bg-gray-700 border border-gray-200 dark:border-gray-600 rounded-lg p-4">
+              <Statistic 
+                title={<span className="text-gray-600 dark:text-gray-400">Progress</span>}
+                value={phase.progress} 
+                suffix="%" 
+                valueStyle={{ color: themeWiseColor('#1890ff', '#40a9ff', themeMode) }}
+              />
+              <Progress 
+                percent={phase.progress} 
+                showInfo={false} 
+                size="small" 
+                strokeColor={themeWiseColor('#1890ff', '#40a9ff', themeMode)}
+                trailColor={themeWiseColor('#f0f0f0', '#4b5563', themeMode)}
+              />
+            </div>
+          </Col>
+          <Col span={6}>
+            <div className="bg-gray-50 dark:bg-gray-700 border border-gray-200 dark:border-gray-600 rounded-lg p-4">
+              <Statistic 
+                title={<span className="text-gray-600 dark:text-gray-400">Tasks</span>}
+                value={phase.completedTaskCount} 
+                suffix={`/ ${phase.taskCount}`}
+                valueStyle={{ color: themeWiseColor('#52c41a', '#34d399', themeMode) }}
+              />
+            </div>
+          </Col>
+          <Col span={6}>
+            <div className="bg-gray-50 dark:bg-gray-700 border border-gray-200 dark:border-gray-600 rounded-lg p-4">
+              <Statistic 
+                title={<span className="text-gray-600 dark:text-gray-400">Milestones</span>}
+                value={phase.completedMilestoneCount} 
+                suffix={`/ ${phase.milestoneCount}`}
+                valueStyle={{ color: themeWiseColor('#722ed1', '#9f7aea', themeMode) }}
+              />
+            </div>
+          </Col>
+          <Col span={6}>
+            <div className="bg-gray-50 dark:bg-gray-700 border border-gray-200 dark:border-gray-600 rounded-lg p-4">
+              <Statistic 
+                title={<span className="text-gray-600 dark:text-gray-400">Team</span>}
+                value={phase.teamMembers.length} 
+                suffix="members"
+                valueStyle={{ color: themeWiseColor('#fa8c16', '#fbbf24', themeMode) }}
+              />
+            </div>
+          </Col>
+        </Row>
+
+        {/* Timeline */}
+        <Row gutter={16} className="mb-6">
+          <Col span={12}>
+            {isEditing ? (
+              <Form.Item name="startDate" label={<span className="text-gray-700 dark:text-gray-300">Start Date</span>}>
+                <DatePicker className="w-full dark:bg-gray-700 dark:border-gray-600" />
+              </Form.Item>
+            ) : (
+              <div className="bg-gray-50 dark:bg-gray-700 border border-gray-200 dark:border-gray-600 rounded-lg p-4">
+                <div className="flex items-center gap-2">
+                  <CalendarOutlined className="text-gray-600 dark:text-gray-400" />
+                  <span className="font-medium text-gray-900 dark:text-gray-100">Start:</span>
+                  <span className="text-gray-600 dark:text-gray-400">{phase.startDate.toLocaleDateString()}</span>
+                </div>
+              </div>
+            )}
+          </Col>
+          <Col span={12}>
+            {isEditing ? (
+              <Form.Item name="endDate" label={<span className="text-gray-700 dark:text-gray-300">End Date</span>}>
+                <DatePicker className="w-full dark:bg-gray-700 dark:border-gray-600" />
+              </Form.Item>
+            ) : (
+              <div className="bg-gray-50 dark:bg-gray-700 border border-gray-200 dark:border-gray-600 rounded-lg p-4">
+                <div className="flex items-center gap-2">
+                  <CalendarOutlined className="text-gray-600 dark:text-gray-400" />
+                  <span className="font-medium text-gray-900 dark:text-gray-100">End:</span>
+                  <span className="text-gray-600 dark:text-gray-400">{phase.endDate.toLocaleDateString()}</span>
+                </div>
+              </div>
+            )}
+          </Col>
+        </Row>
+
+        {isEditing && (
+          <Row gutter={16} className="mb-6">
+            <Col span={12}>
+              <Form.Item name="status" label={<span className="text-gray-700 dark:text-gray-300">Status</span>}>
+                <Select className="dark:bg-gray-700 dark:border-gray-600">
+                  <Select.Option value="not-started">Not Started</Select.Option>
+                  <Select.Option value="in-progress">In Progress</Select.Option>
+                  <Select.Option value="completed">Completed</Select.Option>
+                  <Select.Option value="on-hold">On Hold</Select.Option>
+                </Select>
+              </Form.Item>
+            </Col>
+          </Row>
+        )}
+
+        <Tabs 
+          defaultActiveKey="tasks"
+          className="dark:bg-gray-800"
+          tabBarStyle={{ 
+            borderBottom: `1px solid ${themeWiseColor('#f0f0f0', '#4b5563', themeMode)}`
+          }}
+        >
+          <TabPane tab={`Tasks (${phase.taskCount})`} key="tasks">
+            <List
+              dataSource={phase.tasks}
+              renderItem={(task: PhaseTask) => (
+                <List.Item>
+                  <List.Item.Meta
+                    avatar={getTaskStatusIcon(task.status)}
+                    title={
+                      <div className="flex justify-between items-center">
+                        <Text strong>{task.name}</Text>
+                        <Space>
+                          <Tag color={getPriorityColor(task.priority)}>
+                            {task.priority}
+                          </Tag>
+                          <Progress 
+                            percent={task.progress} 
+                            size="small" 
+                            style={{ width: 100 }}
+                          />
+                        </Space>
+                      </div>
+                    }
+                    description={
+                      <div>
+                        <Text type="secondary">{task.description}</Text>
+                        <div className="mt-2 flex justify-between items-center">
+                          <Space>
+                            <CalendarOutlined />
+                            <Text type="secondary">
+                              {task.startDate.toLocaleDateString()} - {task.endDate.toLocaleDateString()}
+                            </Text>
+                          </Space>
+                          {task.assigneeName && (
+                            <Space>
+                              <TeamOutlined />
+                              <Text type="secondary">{task.assigneeName}</Text>
+                            </Space>
+                          )}
+                        </div>
+                      </div>
+                    }
+                  />
+                </List.Item>
+              )}
+            />
+          </TabPane>
+
+          <TabPane tab={`Milestones (${phase.milestoneCount})`} key="milestones">
+            <Timeline>
+              {phase.milestones.map((milestone: PhaseMilestone) => (
+                <Timeline.Item
+                  key={milestone.id}
+                  color={milestone.isCompleted ? 'green' : milestone.criticalPath ? 'red' : 'blue'}
+                  dot={milestone.isCompleted ? <CheckCircleOutlined /> : <FlagOutlined />}
+                >
+                  <div className="flex justify-between items-start">
+                    <div>
+                      <Text strong>{milestone.name}</Text>
+                      {milestone.criticalPath && (
+                        <Tag color="red" className="ml-2">Critical Path</Tag>
+                      )}
+                      {milestone.description && (
+                        <div className="mt-1">
+                          <Text type="secondary">{milestone.description}</Text>
+                        </div>
+                      )}
+                    </div>
+                    <div className="text-right">
+                      <div>
+                        <CalendarOutlined />
+                        <span className="ml-1">{milestone.dueDate.toLocaleDateString()}</span>
+                      </div>
+                      <Badge 
+                        status={milestone.isCompleted ? 'success' : 'processing'} 
+                        text={milestone.isCompleted ? 'Completed' : 'Pending'}
+                      />
+                    </div>
+                  </div>
+                </Timeline.Item>
+              ))}
+            </Timeline>
+          </TabPane>
+
+          <TabPane tab={`Team (${phase.teamMembers.length})`} key="team">
+            <List
+              dataSource={phase.teamMembers}
+              renderItem={(member: string) => (
+                <List.Item>
+                  <List.Item.Meta
+                    avatar={<Avatar>{member.charAt(0).toUpperCase()}</Avatar>}
+                    title={member}
+                    description={
+                      <Text type="secondary">
+                        {phase.tasks.filter(task => task.assigneeName === member).length} tasks assigned
+                      </Text>
+                    }
+                  />
+                </List.Item>
+              )}
+            />
+          </TabPane>
+        </Tabs>
+      </Form>
+    </Modal>
+  );
+};
+
+export default PhaseModal;